As a video played showing first-year high school English teacher Katie Bonfiglio at work, Spanish teacher Patrice Patton watched in awe.

“Wow, I’ve never seen those kids behave like that in my class,” Patton gushed, as she watched a room of typically restless ninth-grade boys fully engaged in a discussion of literature.

That’s just the reaction Paul Chin, Arlington High School’sassistant principal, was hoping for when he asked Bonfiglio if he could show her recorded lesson to about 15 of her colleagues.

. . . (Bonfiglio) found the discussion with her peers so eye-opening she made changes to some of her other teaching routines.

As a teacher at a high-performing, high-poverty charter school in Newark run by Uncommon Schools, Chin recorded himself teaching so he could analyze his lessons and discuss the video with the principal. He shows Arlington teachers videos of teachers at his old school teaching effectively and helps them analyze their own lessons.

Video recording of teachers also can be used to evaluate teacher performance, which means it’s controversial. Indiana is requiring public schools to create teacher evaluation and rating systems.

Harvard researcher Thomas Kane analyzed 7,500 lessons taught by 1,300 teachers in six school districts for the Methods of Effective Teaching Study, which was funded by the Gates Foundation.

“Digital video may be more valuable than an observer’s notes for allowing a teacher to “see,” literally, the strengths and weaknesses in their practice,” Kane said. “Someone cannot remember what they did not notice in the first place.”

Kane believes all teachers should record themselves teaching and submit “lessons they are proud of” for their performance reviews. “We would then train principals on how to use the video for evaluating and providing productive feedback to teachers.”

TED, a nonprofit known for its annual ideas conference, will provide free video lessons of 10 minutes or less on TED-Ed, reports the Washington Post.

Imagine you’re a high school biology teacher searching for the most vivid way to explain electrical activity in the brain. How about inserting metal wires into a cockroach’s severed leg and making that leg dance to music?

Starting Monday, that eye-popping lesson, performed in a six-minute video by neuroscientist and engineer Greg Gage, is available free online.

“Right now there’s a teacher somewhere out there delivering a mind-altering lesson and the frustrating thing is, it only reaches the students in that class,” said TED-Ed project director Logan Smal­ley. “We’re trying to figure out how to capture that lesson and pair it with professional animators to make that lesson more vivid and put it in a place where teachers all over the world can share it.”

In contrast with many of the free lessons now available online, TED-Ed uses “sophisticated animation, professional editing and high-quality production values,” according to the Post.

Teachers also can find free lessons on YouTube Teachers, a new channel whose slogan is “spend more time teaching, less time searching.”

Differentiated Instruction — grouping students by abilities, personal interests and “learning styles” — is a time-wasting fad that is backed by no evidence of effectiveness, writes education consultant Mike Schmoker in Ed Week.

. . . I saw frustrated teachers trying to provide materials that matched each student’s or group’s presumed ability level, interest, preferred “modality” and learning style. The attempt often devolved into a frantically assembled collection of worksheets, coloring exercises, and specious “kinesthetic” activities. And it dumbed down instruction: In English, “creative” students made things or drew pictures; “analytical” students got to read and write.

In these ways, Differentiated Instruction, or DI, corrupted both curriculum and effective instruction. With so many groups to teach, instructors found it almost impossible to provide sustained, properly executed lessons for every child or group-and in a single class period. It profoundly impeded the teacher’s ability to incorporate those protean, decades-old elements of a good lesson which have a titanic impact on learning, even in mixed-ability classrooms . . .

No research supports DI’s effectiveness, Schmoker writes. Cognitive scientists have debunked the “learning styles” theory that underlies DI. But it is now the reigning orthodoxy.

We know a lot about how to teach well, he argues.

First, we need coherent, content-rich guaranteed curriculum — that is, a curriculum which ensures that the actual intellectual skills and subject matter of a course don’t depend on which teacher a student happens to get.

. . . we need to ensure that students read, write, and discuss, in the analytic and argumentative modes, for hundreds of hours per school year, across the curriculum.

Finally, students learn when “lessons start with a clear, curriculum-based objective and assessment, followed by multiple cycles of instruction, guided practice, checks for understanding (the soul of a good lesson), and ongoing adjustments to instruction.”

In the comments, teachers argue that Schmoker’s definition of effective teaching is differentiated instruction. If so, there’s nothing “differentiated” about DI.